Conventional scalpel blade holders and scalpels have means for detachable or non-detachable fixing of scalpel blades and have a handle region which makes it possible for the user to hold the scalpel, or respectively the scalpel blade holder, with the fingers of one hand. When using scalpels and scalpel blade holders, the user must make sure by means of a glance that he has the instrument in his fingers in such a way that the scalpel blade is correctly aligned and the cutting edge of the scalpel blade faces in the desired direction. To align the scalpel blade, the user must therefore glance away from the place where the operative procedure is supposed to be carried out, which is inconvenient, especially when microscopes or magnifying glasses are being used, and which leads to unnecessary time delays and losses of concentration.